Chapter 1: Group Consensus




  • What are the key chapter elements (take home messages) that I should test you on?




  • What new things are you curious about and/or did not fully understand

Get your global change biologist vibe on



  • Global Change Biology is a new-ish formal field of biology


  • Focused on understanding environmental change and its effects on (and interactions with) life on Earth
    • see handout for the history of terms


  • Represents a pressing need from early career young biologists and recent graduates of any field


  • Communicated many times a day in the news
    • science and non-science communication
    • socioeconomics is now an integral component

Humans are an unprecendented force on natural systems

  • This is largely a numbers and size game
    • 8.1 billion individuals and growing
    • we are not small organisms


  • Environmental change, largely driven by human forcings, impacts most systems across time & space
    • impacts microbes to mammals
    • impacts marine to mountain ecosystems


  • GCB scientists must:
    • understand past environmental change (for context)
    • evaluate current pressures from humans (for degree)
    • predict trends into the future (for decision making)
  • Today: How does the field of GCB work?

The makings of the field of Global Change Biology

  • “On the Influence of Carbonic Acid in the Air upon the Temperature of the Ground.” published by Arrhenius in 1895 while studying ice ages
    • argued that variations in trace atmosphere components (CO2) could greatly influence the heat budget of the Earth
    • Later, he published equations and argued that burning fossil fuels could impact surface temperature


  • Alexander von Humboldt noted that areas surrounding land transformed by agriculture had altered climate (late 1800’s)


  • Guy Callendar published first data linking CO2 and surfaces temperatures in 1938


  • Soon after, studies of the biological impacts of environmental change exploded

What does the field of GCB look like now?



  • Scientific publications are the building blocks of science


  • GCB studies are a key component of the permanent wall of science
    • Now dedicated journals to the field
    • Several high impact journals (Global Change Biology, Nature Climate Change)
    • dedicated books and a few textbooks


  • Note: communicating science outside of formal publishing is essential
    • indigenous ecological knowledge is centuries old


  • Indigenous seasonal calendars are particularly sensitive to climate change both in their biophysical expressions (e.g., earlier flowering phenology of plants or arrival time of migratory birds) and their cultural expressions (e.g., the loss of synchrony between fishing or agricultural practices with life cycles of fishes or plants).

GCB scientists face/d an uphill battle

GCB science is interdisciplinary by necessity


GCB embraces diverse perspectives by necessity

Racist housing policies left neighborhoods sweltering

Scientific bias an have vast socio-economic consequences

Targets, investment, policy and consequences do not align

GCB is diverse but utilizes same scientific principles


  • Vast array of methods due to diversity of fields
    • ecology, evolution, conservation, physiology, etc.


  • Data generated is super diverse
    • observational study → genomics → climate modeling


  • Stressors to be studied are many


  • Time frames needed are not the same
  • All these studies utilize the same design principles
    • Independent and dependent variables
    • Treatments and controls
    • Main effects and interactions


  • Studies must have replication
    • modeling or genomics may be exceptions


  • Studies should have randomization

Review and critical thinking of experimental design



Simply define independent and dependent variables


Why is a control treatment absolutely necessary?


Why does replication matter for statistics?


If there is an interaction effect between 2 variables (say warming and drought) are you allowed to talk about a main effect by itself (say warming)?

GCB science varies in approach

  • Observe and record natural systems undergoing change without manipulation
    • tuskless elephants, length of butterfly tongues, etc.


  • Search for mechanisms by manipulation (treatments)
    • field or laboratory
    • focus on key variables


  • Use math and computers to predict
    • use measured trends to project forward with some level of uncertainity
    • species interactions to global climate


  • Combine many single studies to understand if broad patterns exist
    • may ignore unexpected or negative results


  • Use citizen participation to increase scope

GCB science uses the entire cool science toolkit

  • Environmental monitoring must be expansive
    • land → atmosphere → oceans
    • satellites → lasers → submarines


  • Lots of different organisms to monitor

    • microbes → plants → whales → humans


  • Biodiversity and species responses are key

    • soil microbiome → adaptation → allele diversity
    • molecular biology tools are vital


  • Many experiments or approaches generate large datasets
    • climate monitoring to genomics
    • advanced computing is often necessary